There are at least 10 million video display terminals (hereinafter referred to as "VDTs") in use across the country, and it is predicted that there will be greater than 40 million VDTs by the end of this century. While VDTs are used for a variety of tasks, they are used most intensively by a range of office workers who may spend the entire day keypunching and processing information. It is estimated that keyboard intensive work involves about 18,000 keystrokes per hour by the typist or VDT operator. Each stroke requires the contraction of a muscle and movement of a tendon in the forearm. With high movement rates, there exists a possibility of damage to muscles and tendons as a result of the sliding action. The potential for muscle and tendon damage becomes greater when the arms and hands are used in awkward positions.
If the posture of a VDT operator s wrist is bent, thus bending the carpal tunnel, the tendons swell and the median nerve is compressed. This is referred to as Carpal Tunnel Syndrome and is one of the most common injuries. In addition, a whole variety of repetitive strain injuries, or RSI, are caused by improperly designed VDT work stations. In fact, it has been estimated by the American Academy of Orthopedic Surgeons in 1984 that RSI costs in lost earnings and medically related expenses will exceed $27 billion annually.
Accordingly, in order to prevent such injuries, it is necessary to ensure that the typist's or VDT operator's back, arms and hands be maintained in the proper position for typing. More specifically, the National Institute for Occupational Safety and Health (NIOSH) recommends that typists or VDT operators position the keyboard such that their elbows are bent at angles of 90.degree.. In short, a properly designed work station should allow typists or VDT operators to keep their arms, from elbow to fingertips, in a straight line parallel to the floor so that they do not have to bend their wrists to type. Thus, it is necessary to provide work surfaces that can be adjusted for height, keyboard insets or supports which are adjustable, and adjustable wrist supports so as to permit a typist's or VDT operator's back, arms and wrists to be supported in the proper position.
Referring to FIG. 1, a prior art corner work surface top 1 is illustrated having a VDT 2 positioned thereon. Further, a keyboard inset or support 3 which is movable up and down and also tilts is provided for supporting a keyboard. The keyboard inset is attached underneath the corner work surface top by means of adjustable brackets (see FIG. 2).
As shown in FIG. 2, the prior art keyboard inset is adjustably mounted to the work surface top 1 by means of a pair of L-shaped brackets 4. The brackets 4 are suitably attached to the underside of the work surface such that the vertical portion of each bracket is perpendicular to the work surface 1. As shown in FIG. 3, the vertical portion or longer leg of each L-shaped bracket includes a pair of elongated slots 5 disposed at either longitudinal end of the bracket. An adjustment handle 6 having a threaded shank 7 for threadedly engaging the keyboard inset is positioned in each elongated slot for up and down movement therein. Thus, each bracket has a pair of adjustment handles 6, i.e., a handle positioned in each elongated slot for a total of four handles.
The keyboard inset is a rectangular shaped surface formed of a suitable material such as wood, having a pair of spaced apart holes 8 at each longitudinal end thereof for receiving the threaded shank portion of the respective adjustment handle therein. A t-nut 9 is anchored in each of the above-mentioned holes 8 for threadedly engaging the threaded shank portion 7 of the respective adjustment handle 6. A washer 10 may be placed over the threaded shank portion of each adjustment handle before screwing the handle into the t-nut anchored in the hole of the keyboard inset so as to be positioned between the bracket and the inset. Accordingly, the keyboard inset may be adjusted up and down and tilted by loosening the four handles and manipulating the keyboard inset to the desired position and then again tightening the four handles to lock the inset in the desired position.
However, the problem associated with the prior art keyboard support as shown in FIGS. 1-3 is that the inset is not able to level with the work surface top. Further, the prior art keyboard inset must be thick and heavy in construction in order to support the t-nuts which receive the threaded shanks of the adjustment handles. Also, there is a problem in that the t-nuts tend to pull out of the keyboard inset after continued use.